The present invention relates to a mechanism for transfer of various information concerning individual objectives to a camera body and, more particularly, to such a mechanism adapted to transfer lens side information, such as specific diaphragm value information (fully opened aperture value and minimum aperture value) and diaphragm control changeover information between automatic and manual diaphragm control modes, to the camera body through optical fibers.
As a method for transfer of information available on the lens side (referred to hereinafter as lens side information) such as specific diaphragm value information and control mode changeover information to the camera body, U.S. patent application Ser. No. 237,987, filed Feb. 25, 1981, now U.S. Pat. No. 4,357,089, discloses the method in which the camera body mount and the lens mount opposed to said camera body mount are provided in their mutually confronting surfaces with electrical contacts. The disclosure of this application is incorporated herein by reference.
However, such method of prior art relying upon the electrical contacts has been disadvantageous in that a plurality of electrical contacts must be incorporated into a very small surface areas of respective mounts and electrical insulation must be provided between the respective mounts and the associated electrical contacts. Thus fabrication of such mechanism has been unpractically complicated and difficult.